Game GO

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Game GO

Go is a game of strategy. Two players compete in acquiring territory by placing markers on a smooth wooden board with a simple grid drawn on it, usually 19 by 19 lines. Each player seeks to enclose territory with his markers (called ‘stones’), much like partitioning a field with sections of fencing. Further, each player may capture his opponent’s markers. The object of the game is to enclose the most territory, a simple goal the leads to the elegant and fascinating complexities of go.

Points

A full size go board grid has 19 lines each way, forming a total of 361 points where the grid lines touch one another.
Points win games.
Let's become familiar with counting points on the go board.

Liberties

Each point on the board has lines extending from it. The very next point along a line is an adjacent point. Points are adjacent only along the lines. Any point along a diagonal is not adjacent. Each empty point adjacent to a stone is a liberty.

Forming Connections

Once a stone is placed on a point it is never moved to another point. When a stone of the same color is placed on an adjacent point the two stones are connected. Once connected, stones form an inseparable unit. Thus a single stone, or any number of connected stones, make up a unit.

Capture

Placing stones so as to occupy ALL the liberties of an opposing unit results in NO liberties for that unit and the stones in that unit are captured.

All stones of a captured unit are removed from the board immediately and are retained by the captor as prisoners.

Life & Death

In this Chapter we will now examine ‘safe’ enclosures, and some that are not safe.

In go the players always seek to encircle territory. Often both will be after the same territory at the same time. Sooner or later opposing stones meet and begin to push against each other. Liberties appear and disappear with each play. The conscientious player keeps constant track of the liberties in each unit involved in these territorial battles.

Since stones are captured only when opposing stones occupy all of their liberties, then it follows that: stones cannot be captured if enemy stones cannot occupy all of their liberties. Groups of stones can have ‘safe liberties’, liberties which cannot be filled by the opponent. Such liberties are always surrounded by friendly stones. Hence they must lie inside an ‘enclosure’.

Escape

Stones that retain one or more liberties but have no hope ultimately of keeping any liberties are said to
be dead as they stand or simply ‘dead’.

Stones that are ‘dead as they stand’ remain on the board as long as they retain even one liberty (until the
game is finished, when they will be removed as prisoners).

Two Eyes

An empty point fully enclosed by one color is called an eye. A group of points fully enclosed by one color is also an eye. Stones live by shaping an enclosure of two eyes.

Stones that can form only one eye, or none at all, will eventually come into atari and die.
A stone formation which has two separate eyes will always have at least two liberties.
Thus it can not be captured. The opponent can not fill both eyes at once.

Ending / Scoring

There are four goals in Go: (1) Surround territory, (2) Reduce your opponent's territory, (3) Capture enemy stones, (4) Protect your own stones. The winner, on balance, is always the player who has accomplished these goals more efficiently.

Tying Up the Loose Ends

The game is ended by a pass of turn by each player in sequence. Saying ‘I pass’ means that you see no way to further any of the above goals. Passing presumes that all claimed territories are completely surrounded (all fence sections are in place), and no stones are in atari along the borders between opposing live groups.

Scoring

First verify that all dame have been filled, (with extra stones, not prisoners). Remove from the board, as prisoners, all stones which are dead as they stand. Count each vacant point for the side that has surrounded it. Subtract from black's point count the black prisoners held by white. Do the same for white.

Whichever side has more net points, wins the game.

The Rule of Ko

The word ko means eternity. In go, ko refers to a common situation that would cause ‘stalemate’, an endless series of meaningless plays if there were no rule to cover this occurrence. As things stand here white's three stones at the top are cut off from the others. They appear to be dead as they stand, but - - -. It is white's turn and the black stone which is separating the upper white unit from the lower white stones, is in atari. This ko situation is of great importance to both sides.